::-webkit-input-placeholder {
    color: gray;
}

::-moz-placeholder {
    color: gray;
}

:-ms-input-placeholder {
    color: gray;
}

::-ms-input-placeholder {
    color: gray;
}

::placeholder {
    color: gray;
}

/* 这是一条平平无奇的注释 */
.image {
    background-image: url("image@1x.png");
}

@media (resolution >= 2dppx) {
    .image {
        background-image: url("image@2x.png");
    }
}
